downfile.java

java 多线程下载程序

package down2;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.swing.event.EventListenerList;

import down2.event.MultiDownloadListener;
import down2.event.ThreadNotifyEvent;
import down2.event.ThreadNotifyListener;

/**
 * 
 * <p>Title: DownFile.java</p>
 * <p>Description: </p>
 * <p>Copyright:OnewaveInc Copyright (c) 2007</p>
 * <p>Company: OnewaveInc</p>
 * @author Zhengrw
 * @version 3.0
 */
public class DownFile extends Thread {
	String dlURL;

	String saveFileAs;

	int nthread;

	String info = new String();

	long[] position;

	long[] startPos;

	long[] endPos;

	DownFileSplitter[] downFileSplitter; //子线程对象

	long fileLength;

	boolean stop = false;

	//DataOutputStream output;
	
	private EventListenerList listenerList = new EventListenerList();

	public DownFile(String sURL, String saveFileAs, int nthread) throws IOException {
		this.dlURL = sURL;
		this.saveFileAs = saveFileAs;
		this.nthread = nthread;
		startPos = new long[nthread];
		endPos = new long[nthread];
	}

	public void run() {
		info = "目标文件： " + dlURL;
		System.out.println(info);
		info = "\n 线程总数： " + nthread;
		System.out.println(info);

		try {
			fileLength = getFileSize();
			if (fileLength == -1) {
				System.err.println("不可知的文件长度");
//				textArea.append("\n 不可知的文件长度！请重试！！");
				fireException(ThreadNotifyEvent.DL_EXCEPTION_FILE_LENGTH);
			} else {
				if (fileLength == -2) {
					System.err.println("文件无法获取！");
//					textArea.append("\n 文件无法获取！请重试！！");
					fireException(ThreadNotifyEvent.DL_EXCEPTION_FILE_EXSITS);
				} else {
					for (int i = 0; i < startPos.length; i++) {
						startPos[i] = (long) (i * (fileLength / startPos.length));
					}
					for (int i = 0; i < endPos.length - 1; i++)
						endPos[i] = startPos[i + 1];
					endPos[endPos.length - 1] = fileLength;
					for (int i = 0; i < startPos.length; i++) {
						info = "线程：" + i + "下载范围：" + startPos[i] + "--"
								+ endPos[i];
						System.out.println(info);
//						textArea.append("\n" + info);
						fireNotify(i, ThreadNotifyEvent.DL_NOTIFY_SCOPE,startPos[i],endPos[i]);
					}
					downFileSplitter = new DownFileSplitter[startPos.length];
					//启动一组子线程

					for (int i = 0; i < startPos.length; i++) {
						downFileSplitter[i] = new DownFileSplitter(dlURL,
								saveFileAs, startPos[i], endPos[i], i);
						for(MultiDownloadListener listener : this.listenerList.getListeners(MultiDownloadListener.class)){
							downFileSplitter[i].addMultiDownloadListener(listener);
						}
						info = "线程 " + i + "启动";
//						textArea.append("\n" + info);
						fireNotify(i, ThreadNotifyEvent.DL_NOTIFY_START);
						downFileSplitter[i].start();
						System.out.println(info);
					}

					boolean breakWhile = true;
					while (breakWhile) {
						Thread.sleep(500);
						breakWhile = false;
						for (int i = 0; i < downFileSplitter.length; i++) {
							if (!downFileSplitter[i].done) {
								breakWhile = true;
								break;
							}
						}
					}
					System.out.println("文件传输结束！");//文件传输结束
//					textArea.append("\n 文件传输结束！");
					fireNotify( ThreadNotifyEvent.DL_NOTIFY_FILE_END);
				}
			}
		} catch (Exception ex) {
			ex.printStackTrace();
		}

	}

	public long getFileSize() {
		int fileLength = -1;
		try {
			URL url = new URL(dlURL);
			HttpURLConnection httpConnection = (HttpURLConnection) (url
					.openConnection());
			int responseCode = httpConnection.getResponseCode();
			if (responseCode >= 400) {
				System.out.println("Web服务器响应错误");
				return -2;//Web服务器响应错误
			}
			String sHeader;
			for (int i = 1;; i++)//查找标识文件长度的文件头，获取文件长度
			{
				sHeader = httpConnection.getHeaderFieldKey(i);
				if (sHeader != null) {
					if (sHeader.equals("Content-Length")) {
						fileLength = Integer.parseInt(httpConnection
								.getHeaderField(sHeader));
						break;
					}
				} else {
					break;
				}
			}
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return fileLength;

	}
	
	private void fireException(int type){
		ThreadNotifyEvent event = new ThreadNotifyEvent(this);
		event.setType(type);
		for(ThreadNotifyListener listener : this.listenerList.getListeners(ThreadNotifyListener.class)){
			listener.exceptionOccured(event);
		}
	}
	
	private void fireNotify(int type){
		fireNotify(0,type);
	}
	private void fireNotify(int threadID,int type){
		ThreadNotifyEvent event = new ThreadNotifyEvent(this);
		event.setThreadId(threadID);
		event.setType(type);
		for(ThreadNotifyListener listener : this.listenerList.getListeners(ThreadNotifyListener.class)){
			listener.notifyInfo(event);
		}
	}
	
	private void fireNotify(int threadID,int type,long start,long end){
		ThreadNotifyEvent event = new ThreadNotifyEvent(this);
		event.setThreadId(threadID);
		event.setType(type);
		event.setStart(start);
		event.setEnd(end);
		for(ThreadNotifyListener listener : this.listenerList.getListeners(ThreadNotifyListener.class)){
			listener.notifyInfo(event);
		}
	}
	
	public void addThreadNotifyLitener(ThreadNotifyListener listener){
		this.listenerList.add(ThreadNotifyListener.class, listener);
	}
	
	public void removeThreadNotifyLitener(ThreadNotifyListener listener){
		this.listenerList.remove(ThreadNotifyListener.class, listener);
	}
	
	public void addMultiDownloadListener(MultiDownloadListener listener){
		this.listenerList.add(MultiDownloadListener.class, listener);
	}
	
	public void removeMultiDownloadListener(MultiDownloadListener listener){
		this.listenerList.remove(MultiDownloadListener.class, listener);
	}

}